Based on material copyright 1970 Magazine Management; 1966 Canam Publishers Sales Corp; 1966 Olympia Publications Inc. Marvel Comics Group a division of Cadence Industries Corp., NY, NY. "Not to be sold in the United Sates of America or Canada. Printed in Finland. Savon Sanomain Kirjapaino Oy Kuopio 1974." No indicia frequency, but cover is dated "Week ending November 2, 1974" -- so presumably weekly.
Kirby's role as co-plotter has been acknowledged in many interviews by Lee and Kirby.